scholarly journals Landau theory of the phase transitions in half-doped manganites: Interplay of magnetic, charge, and structural order

2000 ◽  
Vol 61 (5) ◽  
pp. 3192-3195 ◽  
Author(s):  
Fan Zhong ◽  
Z. D. Wang
Keyword(s):  
Phase Transitions ◽  
Magnetic Charge ◽  
Landau Theory ◽  
Structural Order ◽  
Doped Manganites

Landau theory of phase transitions in TTF-TCNQ

1980 ◽  
Vol 41 (7) ◽  
pp. 677-699 ◽  
Author(s):  
C. Hartzstein ◽  
V. Zevin ◽  
M. Weger
Keyword(s):  
Phase Transitions ◽  
Landau Theory

scholarly journals Magnetic-charge ordering and phase transitions in monopole-conserved square spin ice

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Y.-L. Xie ◽  
Z.-Z. Du ◽  
Z.-B. Yan ◽  
J.-M. Liu
Keyword(s):  
Phase Transitions ◽  
Magnetic Charge ◽  
Charge Ordering ◽  
Spin Ice

Landau theory of second-order phase transitions in ferroelectric films

2001 ◽  
Vol 63 (14) ◽  
Author(s):  
Lye-Hock Ong ◽  
Junaidah Osman ◽  
D. R. Tilley
Keyword(s):  
Phase Transitions ◽  
Landau Theory ◽  
Second Order ◽  
Ferroelectric Films

Green Function Calculations of Properties for the Magnetocaloric Layered Structures Based Upon FeMnAsP

SPIN ◽  
2016 ◽  
Vol 06 (03) ◽  
pp. 1650010
Author(s):  
Osvaldo F. Schilling
Keyword(s):  
Magnetic Field ◽  
Phase Transitions ◽  
Green Function ◽  
Landau Theory ◽  
Random Phase ◽  
Layered Structures ◽  
Continuous Phase ◽  
Theoretical Treatment ◽  
Entropy Variation ◽  
Commercial Applications

The alternating Fe–Mn layered structures of the compounds FeMnAsxP[Formula: see text] display properties which have been demonstrated experimentally as very promising as far as commercial applications of the magnetocaloric effect are concerned. However, the theoretical literature on this and other families of magnetocaloric compounds still adopts simple molecular-field models in the description of important statistical mechanical properties like the entropy variation that accompanies applied isothermal magnetic field cycling, as well as the temperature variation following adiabatic magnetic field cycles. In the present paper, a random phase approximation Green function theoretical treatment is applied to such structures. The advantages of such approach are well known since the details of the crystal structure are easily incorporated in the model, as well as a precise description of correlations between neighbor spins can be obtained. We focus on a simple one-exchange parameter Heisenberg model, and the observed first-order phase transitions are reproduced by the introduction of a biquadratic term in the Hamiltonian whose origin is related both to the magnetoelastic coupling with the phonon spectrum in these compounds as well as with the values of spins in the Fe and Mn ions. The calculations are compared with experimental magnetocaloric data for the FeMnAsxP[Formula: see text] compounds. In particular, the magnetic field dependence for the entropy variation at the transition temperature predicted from the Landau theory of continuous phase transitions is reproduced even in the case of discontinuous transitions.

On the Structural Phase Transitions in (C2H5NH3)2FeCl4. II. Landau Theory

1985 ◽  
Vol 54 (12) ◽  
pp. 4607-4620 ◽  
Author(s):  
Akira Yoshihara ◽  
Takashi Suzuki ◽  
Tadao Fujimura
Keyword(s):  
Phase Transitions ◽  
Landau Theory ◽  
Structural Phase ◽  
Structural Phase Transitions

The Landau theory of phase transitions: A mechanical analog

Resonance ◽  
2009 ◽  
Vol 14 (7) ◽  
pp. 704-713
Author(s):  
Rekha S. Raorane ◽  
Raghu Mahajan ◽  
Praveen Pathak ◽  
Vijay A. Singh
Keyword(s):  
Phase Transitions ◽  
Landau Theory ◽  
Mechanical Analog
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